100760-04-1Relevant articles and documents
C1-Symmetric PNP Ligands for Manganese-Catalyzed Enantioselective Hydrogenation of Ketones: Reaction Scope and Enantioinduction Model
Zeng, Liyao,Yang, Huaxin,Zhao, Menglong,Wen, Jialin,Tucker, James H. R.,Zhang, Xumu
, p. 13794 - 13799 (2020)
A family of ferrocene-based chiral PNP ligands is reported. These tridentate ligands were successfully applied in Mn-catalyzed asymmetric hydrogenation of ketones, giving high enantioselectivities (92%～99% ee for aryl alkyl ketones) as well as high efficiencies (TON up to 2000). In addition, dialkyl ketones could also be hydrogenated smoothly. Manganese intermediates that might be involved in the catalytic cycle were analyzed. DFT calculation was carried out to help understand the chiral induction model. The Mn/PNP catalyst could discriminate two groups with different steric properties by deformation of the phosphine moiety in the flexible 5-membered ring.
Iron achieves noble metal reactivity and selectivity: Highly reactive and enantioselective iron complexes as catalysts in the hydrosilylation of ketones
Bleith, Tim,Wadepohl, Hubert,Gade, Lutz H.
, p. 2456 - 2459 (2015)
Chiral iron alkyl and iron alkoxide complexes bearing boxmi pincers as stereodirecting ligands have been employed as catalysts for enantioselective hydrosilylation reactions with unprecedented activity and selectivity (TOF = 240 h-1 at -40 °C, ee up to 99% for alkyl aryl ketones), which match the performance of previously established noble-metal-based catalysts. This shows the potential of earth-abundant metals such as iron for replacing platinum-metals without any drawbacks for the reaction design.
Practical and efficient procedure for the in situ preparation of B-alkoxyoxazaborolidines. Enantioselective reduction of prochiral ketones
Ponzo, Viviana L.,Kaufman, Teodoro S.
, p. 495 - 496 (2000)
A new method for the in situ elaboration of B-alkoxyoxazaborolidines is presented. Their use in the enantioselective reduction of prochiral aromatic ketones provides excellent chemical and optical yields of chiral alcohols.
An efficient Ir(III) catalyst for the asymmetric transfer hydrogenation of ketones in neat water
Li, Xiaohong,Blacker, John,Houson, Ian,Wu, Xiaofeng,Xiao, Jianliang
, p. 1155 - 1160 (2006)
The chiral M-CsDPEN [M = Ru, Rh, Ir; CsDPEN = (R,R,R)- or (S,S,S)-N-camphorsulfonyl-1,2-diphenylethylenediamine] catalysts have been shown to be efficient for the asymmetric transfer hydrogenation (ATH) of aryl ketones by formate in neat water. Of particular note is the Ir-(R,R,R)-CsDPEN catalyst, which catalyzes the ATH of a wide range of ketones and delivers almost full conversions within a few hours at a S/C ratio of 1000 at 40 °C in most cases, with enantioselectivities up to 98% ee. Georg Thieme Verlag Stuttgart.
Asymmetric hydrosilylation of ketones catalyzed by magnetically recoverable and reusable copper ferrite nanoparticles
Kantam, M. Lakshmi,Yadav, Jagjit,Laha, Soumi,Srinivas, Pottabathula,Sreedhar, Bojja,Figueras
, p. 4608 - 4611 (2009)
(Chemical Equation Presented) Herein we present magnetically recoverable and reusable copper ferrite nanoparticles for asymmetric hydrosilylation of several ketones. Up to 99% enantiometric excess was obtained at room temperature using polymethylhydrosiloxane as the stoichiometric reducing agent. The copper ferrite nanoparticles were magnetically separated, and the efficiency of the catalyst remains almost unaltered up to three cycles.
Imidazolium ion tethered TsDPENs as efficient water-soluble ligands for rhodium catalyzed asymmetric transfer hydrogenation of aromatic ketones
Kang, Guowei,Lin, Silong,Shiwakoti, Atul,Ni, Bukuo
, p. 111 - 114 (2014)
An imidazolium ion tethered TsDPEN has been synthesized readily and used as a water-soluble ligand for [Cp*RhCl2]2 catalyzed asymmetric transfer hydrogenation (ATH) of aromatic ketones in water. This process provided the secondary alcohols in moderate to excellent conversions (up to 100%) with high enantioselectivities (up to 98% ee) under mild reaction conditions without adding any surfactants. The catalytic system is highly effective with the substrate to catalyst (S/C) ratio of 500 and low hydride donor loading of 1.5 equiv. of HCO2Na. The procedure presented is simple and makes this method suitable for practical use.
Optimisation, scope and advantages of the synthesis of chiral phenylethanols using whole seeds of Bauhinia variegata L. (Fabaceae) as a new and stereoselective bio-reducer of carbonyl compounds
Aimar, Mario L.,Bordón, Daniela L.,Cantero, Juan J.,Decarlini, María F.,Demmel, Gabriela I.,Rossi, Laura I.,Ruiz, Gustavo M.,Vázquez, Ana M.
, p. 1 - 15 (2020)
With the aim of finding new methods for environmentally friendly synthesis of chiral phenylethanols, a screening was carried out to identify seeds that could be used as a biocatalyst capable of reducing stereoselectively prochiral ketones. As a result, seeds of Bauhinia variegata L. (Fabaceae) were identified as being an efficient and stereoselective biological reducer of acetophenone to produce (S)-1-phenylethanol (conversion of 98% and 99 e.e.%). Then, to optimise the reductive process, the effects of some variables such as temperature, load of substrate, pH, co-solvent, and reuse and storability of the seeds as a function of time were established. Utilising the optimal reaction conditions, nineteen substituted acetophenones were reduced to their corresponding chiral alcohols with a conversion ranging from 30% to 98% and enantiomeric excess of between 65% and >99%, and in addition, useful key intermediates were also obtained by the synthesis of drugs. The scope and advantages of this new biocatalytic synthetic method are also discussed.Research highlights A screening was carried out to identify seeds that could be used as a biocatalyst Seeds of Bauhinia variegata have been identified as an efficient biocatalyst to reduce carbonyl compounds. Acetophenone and substituted acetophenones were reduced with high stereoselectivity. Some key intermediates were synthetised using this methodology. Seeds can be stored for twenty-four months without loss of activity.
New air-stable iron catalyst for efficient dynamic kinetic resolution of secondary benzylic and aliphatic alcohols
Yang, Qiong,Zhang, Na,Liu, Mingke,Zhou, Shaolin
, p. 2487 - 2489 (2017)
We herein report a catalyst system for the dynamic kinetic resolution of secondary alcohols by combining the enzymatic resolution with an iron-catalyzed racemization. A new air-stable tricarbonyl (cyclopentadienone)iron complex is identified as the active racemization catalyst for this transformation without any additive. Various substrates including benzylic, heteroaromatic, aliphatic alcohols can be used and afford the corresponding esters in good yields and with excellent enantioselectivities.
Asymmetric palladium-catalyzed hydrosilylation of styrenes using efficient chiral spiro phosphoramidite ligands
Guo, Xun-Xiang,Xie, Jian-Hua,Hou, Guo-Hua,Shi, Wen-Jian,Wang, Li-Xin,Zhou, Qi-Lin
, p. 2231 - 2234 (2004)
Asymmetric hydrosilylation of styrene derivatives with trichlorosilane in the presence of palladium complexes of chiral spiro phosphoramidites provided 1-aryl-1-silylalkanes as single regioisomers in high yields, which have been oxidized with hydrogen peroxide to give the corresponding chiral alcohols in up to 99.1% ee.
Catalytic Asymmetric Addition of Organolithium Reagents to Aldehydes
Veguillas, Marcos,Solà, Ricard,Shaw, Luke,Maciá, Beatriz
, p. 1788 - 1794 (2016)
Herein we report an efficient catalytic system for the titanium-promoted enantioselective addition of organolithium reagents to aldehydes, based on chiral Ar-BINMOL ligands. Unprecedented yields and enantioselectivities are achieved in the alkylation reactions of aliphatic aldehydes. Remarkably, methyllithium can be added to a wide variety of aromatic and aliphatic aldehydes, providing versatile chiral methyl carbinol units in a simple one-pot procedure under mild conditions and in very short reaction times.
